1. Field of the Invention
This invention relates generally to fuel filters and methods for making same, and more particularly to such fuel filters not requiring curing processes in their manufacture.
2. Description of the Related Art
Most fuel filters include a non-removable cylindrical shaped filter element comprised of an elongated pleated paper filter media having an annular cap at each end. The present method of manufacturing fuel filters containing these pleated paper filter elements is not only time consuming, but presents a number of environmental concerns, health related issues, and unpleasant working conditions due to the release of formaldehyde and hydrocarbons into the manufacturing plant and atmosphere in general from the cure of the filter paper and adhesives required to manufacture the filter elements. Additionally, these adhesives contain chemicals with which manufacturing personal may come in contact with during the manufacturing process.
The following description illustrates the problems associated with the present method of manufacturing pleated paper filter elements. The paper filter media used in such fuel filters is usually supplied to the fuel filter manufacturer from an outside vendor who fabricates the paper filter media in compliance with the filter manufacturer's specifications and delivers it in large 36 inch diameter rolls of varying widths. These large filter paper rolls are then loaded onto a pleating machine which is set to the desired pleat height and width to satisfy the specifications for the filter element. After the filter paper is threaded into the pleating machine and pleated, the pleated filter paper travels down a heated line to a cutting machine which may be automated or manual. The pleats are counted and the paper is cut to the correct number of pleats required for the filter element being manufactured. The cut filter media then moves to the welding operation and is rolled and welded into a cylindrical shape having an unfinished length. These cylinder shaped lengths of pleated filter paper are then cut to a finished length or "broken" to a finished length if the filter paper is purchased in "slit" widths. Next, one end of each finished length of the cylinder shaped pleated filters, referred to hereinafter as the paper element, is placed into an annular adhesive filled end cap. A non-adhesive-filled annular end cap is placed on the other end of the paper element to hold the shape of the unfinished filter element. This assembly is then placed in a first bake oven. When the adhesive is cured, the assembly exits the first bake oven. The non-adhesive filled end cap is removed and the assembly is turned over and placed into another annular adhesive filled end cap. This final assembly is then placed into the final bake oven to cure the adhesive in the second end cap and to cure the paper element, resulting in a finished filter element. The finished filter element is then placed into a filter element housing. A filter housing end cap is then press fit and seal welded to the filter element housing resulting in a completed fuel filter.
As should be evident from the above description, there is a considerable amount of wasted or down time in the present method of manufacturing fuel filters containing the conventional pleated paper elements. First, as discussed above, the present method requires the baking of the filters to cure the adhesives. Depending on the ovens being used, it may take 20 to 40 minutes for the filter elements to pass through each oven. Second, more time is wasted while the baking ovens are warming-up to the necessary temperature for the curing process. Third, at breaks and at the ends of shifts, the oven cannot be loaded for the last 20 to 40 minutes in order to ensure that all the filters are cleared from the ovens.
Thus, there is a need in the fuel filter manufacturing industry for a "no-cure" fuel filter element. By eliminating the necessity to cure the adhesives, there is no need for ovens which will save the manufacturer in equipment costs, maintenance and energy consumption. Additionally, with no-cure fuel filter elements, more filters can be produced per hour with less personal, because numerous steps in the manufacturing process can be eliminated and because with the no-cure process, filters can be manufactured from the start of the shift, right up to breaks and right to the end of the shift, rather than having to wait for the ovens to warm up, wait for the filters to pass through the ovens, and having to stop loading the ovens 20 to 40 minutes before the end of the shift.
Additionally, by eliminating adhesives and the oven curing processes, the worker's environment and the environment in general will be improved due to the elimination of the unpleasant odors caused by the release of formaldehyde into the atmosphere by the paper filter media during the curing process, due to the elimination of the release of hydrocarbons into the atmosphere during the curing of the adhesive, and due to the elimination of potential contact of the workers with the chemicals found in the adhesives.
Those concerned with these and other problems recognize the need for an improved no-cure fuel filter and method of making the same